Comparative study of rate of retraction and molar control between Dual Dimensional wires and Rectangular wires during retraction, using Miniscrews

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A COMPARATIVE STUDY OF RATE OF RETRACTION AND

MOLAR CONTROL BETWEEN DUAL DIMENSIONAL WIRES

AND RECTANGULAR WIRES DURING RETRACTION,

USING MINISCREWS

Dissertation Submitted to

THE TAMILNADU DR. M. G.R. MEDICAL

UNIVERSITY

For partial fulfillment of the requirements for the degree of

MASTER OF DENTAL SUR GERY

BRANCH – V

ORTHODONTICS AND DENTOFACIAL ORTHOPAEDICS

THE TAMILNADU DR. M.G.R MEDICAL UNIVERSITY

CHENNAI – 600 032

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ACKNOWLEDGEMENT

First of all, I seek the blessings of the Almighty God without whose benevolence; the study would not have been possible.

I take this opportunity to thank my parents Mrs.Padmini and Mr.Gnanesh, my Husband Dr.Nagesh D.M.,and my adorable kids Mas.Ruhann and Mas.ryann for their endless patience during the entire period of this three years of course.

It is my privilege and great honour to express my gratitude to my respected guide and Principal Dr. SRIDHAR PREMKUMAR, M.D.S., Professor,Department of Orthodontics and Dentofacial Orthopaedics, Tamilnadu Govt.Dental College and Hospital, Chennai-3, for his conceptualization,patience guidance, support and encouragement throughout the study and during the three years of course.

I express my deep sense of gratitude and honour to my respected

Professor and Head, Dr. G.Vimala M.D.S., Department of Orthodontics and Dentofacial Orthopaedics, Tamilnadu Govt. Dental College and Hospital, Chennai-3, for her constant inspiration and encouragement throughout the entire course.

I owe my thanks to Dr.Balashanmugam,M.D.S.,Professor, Department of Orthodontics and Dentofacial Orthopaedics, Tamilnadu Govt. Dental College and Hospital, Chennai-3, for helping me with his valuable suggestions and encouragement.

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I thank Dr.Mohammad Junaid., for helping me with the Statistics in the study.

I offer my gratitude to my patients who expressed complete cooperation for the successful completion of this study

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TRIPARTITE AGREEMENT

This agreement herein after the “Agreement” is entered into on this

day... day of December 2014 between the Tamil Nadu Government Dental College and Hospital represented by its Principal having address at Tamilnadu Government Dental college and Hospital, Chennai-03, (hereafter referred to as the ‘college’

And

Dr.SRIDHAR PREMKUMAR aged 47 years working as professor in the Department of Orthodontics and Dentofacial orthopaedics, at the college, having residence address at B-3, Block 2, Jains Ashraya Phase III, Arcot road,Virugambakkam, Chennai-92. (herein after referred to as the ‘Principal investigator’)

And

Dr.Sangeetha.M.G.aged 36 years currently studying M.D.S (Orthodontics) in Tamilnadu Government Dental college and Hospital (herein after referred to as the ‘PG/Research student and co- investigator’).

Whereas the ‘PG/Research student as part of his curriculum undertakes to

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1. The parties agree that all the Research material and ownership therein shall become the vested right of the college, including in particular all the copyright in the literature including the study, research and all other related papers.

2. To the extent that the college has legal right to do go, shall grant to licence or assign the copyright do vested with it for medical and/or commercial usage of interested persons/entities subject to a reasonable terms/conditions including royalty as deemed by the college.

3. The royalty so received by the college shall be divided equally by all the parties.

4. The PG/Research student and PG/Principal Investigator shall under no circumstances deal with the copyright, Confidential information and know how generated during the course of research/study in any manner whatsoever, while shall sole vest with the manner whatsoever and for any purpose without the express written consent of the college.

5. All expenses pertaining to the research shall be decided upon by the principal investigator/Co-investigator or borne sole by the PG/research student(co-investigator).

6. The college shall provide all infrastructure and access facilities within and in other institutes to the extent possible. This includes patient interactions, introductory letters, recommendation letters and such other acts required in this regard.

7. The principal investigator shall suitably guide the student Research right from selection of the Research Topic and Area till its completion. However the selection and conduct of research, topic and area research by the student researcher under guidance from the principal investigator shall be subject to the prior approval, recommendations and comments of the Ethical Committee of the college constituted for this purpose.

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9. If any dispute arises as to the matters related or connected to this agreement herein, it shall be referred to arbitration in accordance with the provisions of the Arbitration and Conciliation Act, 1996.

10. In witness whereof the parties hereinabove mentioned have on this the day month and year herein above mentioned set their hands to this agreement in the presence of the following two witnesses.

College represented by its

Principal PG Student

Witnesses Student Guide

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ABSTRACT

Introduction: Conventional rectangular wires used for retraction of anteriors in

premolar extraction cases, causes increased resistance to sliding due to various

factors like stiffness friction, binding etc., thereby increases the treatment time and

also puts a strain on the molars due to the reciprocating forces of retraction. Dual

Dimensional wire has been used in this study to reduce the resistance and allow

easy sliding of the archwire during retraction, along with good control of molars

with the help of miniscrews as direct anchorage.

Aim and Objectives: To study the rate of space closure and molar control

between Dual Dimensional wire and Rectangular wire during retraction using

miniscrews. To compare the rate of space closure and molar control between the

above two wires.

Materials and Methods: Sixteen patients, chosen in the age group of 17-25,who

fulfilled the inclusion and exclusion criteria were segregated as Group A and B,

for Dual Dimensional wire and conventional Rectangular wire respectively.

Models, Cephalograms were taken before and after the study period (4

months).Clinical procedure involved placing the microimplants and the wires in

the respective groups followed by retraction with NiTi coil springs, attached

between the implant head and S hook fixed mesial to canine. At the end of study

period, results were analysed using SPSS software .

Results: The results showed significant difference in the amount of space closure

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DDW group, in the given study period. The mean change in the amount of space

closure was 4.01mm and 3.31 mm in DDW and Rectangular wire group

respectively. Mesial tangent on the right molars showed marginal significance

(0.049). Minor changes were observed in the position of molars in both the groups

with more changes in the Rectangular wire, though the changes were statistically

insignificant.

Conclusion: In the era of low friction systems and Microimplant, it becomes

prudent to choose Dual Dimensional wire over conventional wire for smooth and

easy sliding of archwire during retraction, when miniscrews act as anchorage

provider, to control the molars, and hence faster tooth movement leading to

reduced retraction time for space closure, in orthodontic treatments.

Keywords: Dual Dimensional wire, rectangular wire, NiTi coil spring,

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ABBREVIATIONS

MESDIS Mesiodistal measurement of extraction space in millimeters

LONGAXIS Horizontal distance between the longaxis of 2nd premolar and canine in millimeters

PTV-6- Horizontal distance between pt v to distal of 1st molar in millimeters

ANG SN 6- Angle between sn plane and 1st molar in degrees BA-N6,PM,M Basion-nasion plane to 1st molar,2nd premolar and

canine in degrees

SPACE 13-15 Space present between 13 and 15 in millimeters

SPACE 23-25 Space present between 23 and 25 in millimeters

MID C RT Midline to right canine in millimeters

MID C LT Midline to left canine in millimeters

MID PM RT Midline to right premolar in millimeters

MID PM LT Midline to left premolar in millimeters MID M RT Midline to right molar in millimeters

MID M LT Midline to left molar in millimeters

M ANG DIS RT Midline to right molar distal tangent in degrees

M ANG MES RT Midline to right molar mesial tangent in degrees

M ANG DIS LT Midline to right molar mesial tangent in degrees

M ANG MES LT Midline to right molar distal tangent in degrees

I.P.-6 Anteroposterior distance from incisive papilla to the

reference points drawn from the central pit of 1st

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I.P.-5 Anteroposterior distance from incisive papilla to the

reference points drawn from the central pit of 2nd

premolar in millimeters

I.P.-3 Anteroposterior distance from incisive papilla to the reference points drawn from the central pit of canine in millimeters.

I.P. Incisive papilla Perpendicular

IOPA Intra oral periapical radiographs

SPSS Statistical Package for Social Sciences

MIA Mini implant Anchorage

T 0 Pre-treatment

T1 Post-treatment

MBT Mc laughlin Bennet Trevisi

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INTRODUCTION

The success of any treatment lies in choosing the right materials and

techniques, to bring forth the required changes when preserving the rest of the

environment. It holds true for Orthodontic treatments too. It is preferable to

achieve the required tooth movement with the rest of the teeth or occlusion

unharmed. Of all the treatments done in Orthodontics, retraction of Proclined

anterior teeth forms a very important and common procedure. Retraction can be

simply defined as moving the teeth Posteriorly. It is done mainly by 1.Enmasse or

2. Two stage retraction (separate canine retraction).

Although the two steps procedure is predictable and has excellent fail-safe

characteristics, it takes longer to close space in two steps than one. so, enmasse

retraction is recommended1..To maximize the utility of the extraction space for

retraction of anteriors, in premolar extraction cases it is essential to control the

amount of incisor retraction vs. molar-premolar protraction. Preventing the

posteriors from moving forward into the extraction space (Anchorage control)- is

an essential part of treatment planning in Orthodontics.

The reasons for anchorage loss are excessive force, improper anchorage

preparation, impingement of the roots of the incisors or anterior teeth to the labial

cortical plate etc. The common methods to prevent anchorage loss are by using

anchorage savers like 1. Tranpalatal arches, lingual arches, nance palatal

arches.2.use of optimum force 3.usage of differential force4.reinforcemnt of

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But Anchor loss is almost inevitable and is one of the major causes of

prolonged treatment time and unsuccessful treatment outcome. One of the main

reason for loss of molar control is the resistance and friction produced by the

stiffer wires used during retraction. Rectangular wires are used for space closure,

after alignment and leveling of comprehensive orthodontic treatment with sliding

mechanics. One of the main disadvantage of these wires is that they generate

reciprocating forces between the anterior and posterior teeth during retraction,

when movement (mesial) of posteriors are unwanted. It is ideal to have retracting

forces in the anterior section and mild forces or nil force in the posteriors .It takes

more time to close the extraction space with these stiffer rectangular wires, as they

resist easy sliding of the wire distally, due to various factors such as increased

wire size ,friction requiring more force etc., which often results in anchor loss as

well, leading to the loss of extraction space available, to be used for anterior

retraction or correction. Conventional wisdom states that an orthodontist must

apply added force to overcome friction, the result of which can be increased

anchorage loading and subsequent anchorage loss.

If the teeth are free to slide along the archwire, friction between brackets

and archwires does not increase anchorage loading. The ideal in the use of sliding

mechanics would be to find the best combination of arch wire size, slot size, and

force which would translate a tooth along an arch wire with minimal friction,

without excessive tipping, and without unduly disturbing anchorage.

Introduction of Skeletal anchorage in Orthodontics by Creekmore, T. and

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treatment mechanics. Miniscrews and Miniplates3 offers the possibility of various

tooth movements with reduced or minimum anchor loss and lesser need for patient

compliance. Studies have proved that they provide excellent molar control. So,

Miniscrew usage has become an important milestone in recent orthodontics.

This study was undertaken with the hypothesis that easy sliding of the

archwire distally along with anterior torque control, during retraction produces

effective teeth movement, if the retracting forces are from miniscrews, which

allows us to have improved molar control as well, leading to the success of the

treatment.

To achieve anterior torque control along with reduced resistance to sliding

of the archwire,during space closure,bidimensional system4 was introduced. Dual

Dimensional wires5 with two different dimensions were introduced as a

Bidimensional system .These are Orthodontic wires with two different dimensions

in the same continuous archwire. The anterior section is square or rectangular and

posterior section is round.

This combination produces effective anterior retraction with minimal

change in the position of posteriors, during space closure. With the conventional

wires molar control is usually an issue but when miniscrews provide anchorage,

these dual dimensional wires slide freely in the molar tube distally, because of the

round cross section in the posterior region, allowing faster space closure with

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AIMS AND OBJECTIVES

AIM

To study and compare the rate of retraction and molar control between

Dual Dimensional wires and Rectangular wires during retraction, using

miniscrews.

OBJECTIVES

1. To study the rate of space closure, molar control during retraction ,using

dual dimension wire (DDW)

2. To study the rate of space closure, molar control during retraction, using

conventional rectangular wires.

3. To compare the rate of space closure, molar control during retraction,

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REVIEW OF LITERATURE

1. sliding mechanics and Anchor loss

2. Friction and Archwire

3. Retraction with Miniscrews

4. Bidimensional system

5. Dual Dimensional Wire

SLIDING MECHANICS

Charles CR.6 (1982) explained that the most of the methods of canine retraction

have their inherent advantages and disadvantages. The retraction systems which

slide canines along a relatively rigid archwire, would appear to have the advantage

of achieving better controlled apical and crown movement but at the obvious cost

of greater friction and binding than the sectional arch.If sliding mechanics are

used either with a J hook headgear to canines or elastic intra-traction from the

molars, it would seem advisable to use a heavy round wire in at least a medium

width bracket. To help decrease binding when using elastic traction, power arms

would certainly seem to have a place, with the added benefit of patients having an

accessible hook to change elastics themselves.

Ulgen M.7 (1990) Space closure in frictional mechanics has usually been

performed in two stages to avoid straining the anchorage teeth; however, this

technique is usually more time-consuming than one-stage (en masse) retraction,'

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J.A.Von Fraunhofer and B.E.Johnson8 (1993) in their article force generation

by orthodontic coil springs, said that efficient, biological tooth movement by

means of light continuous forces is the preferred treatment modality in

contemporary orthodontics. Their findings indicated that the niti coil springs

would deliver a relatively constant force over a range of 7 mm tooth movement

with one activation and also that NITI coil springs appeared to be superior choice

to consistently deliver light continuous forces while moving teeth and practical

too.

Kusy RP 9(2000) said that the resistances to sliding (RS) were measured in vitro

for various archwires against stainless steel brackets. Using stainless steel

ligatures, a constant normal force (300g) was maintained while second-order

angulation (straight theta) was varied from -12 degrees to +12 degrees. Using

miniature bearings to simulate contiguous teeth, five experiments each were run in

the dry or wet states with human saliva at 34 degrees C as a function of four

archwire alloys, five interbracket distances, and two bracket engagements.

Outcomes were objectively analyzed to establish when theta=0, and the relative

contact angles (theta - r) were replotted. Stiffer archwires and shorter interbracket

distances exacerbated binding, whereas, once corrected for differing bracket

engagement, RS was independent of slot dimension.

Joon-No Rhee10 (2001), his study was designed to explore the differences

between friction and frictionless mechanics for maxillary canine retraction with

the use of a new typodont simulation system, the Calorific machine system. The

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composed of 3 parts: a temperature regulating system, electrothermodynamic

teeth, and an artificial alveolar bone component. The efficiency of maxillary

canine retraction was compared with the sliding mechanics (along a .016 × .022–

in stainless steel labial arch and nickel-titanium closed coil spring) and a canine

retraction spring. The patterns of tooth movement obtained with both of these

mechanics were measured 5 times each. Friction mechanics were superior to

frictionless mechanics in terms of rotational control and dimensional maintenance

of the arch (P < .0001); frictionless mechanics were shown to be more effective at

reducing tipping and extrusion (P < .0001 ).

Tominaga11 (2009) studied measures to determine optimal loading conditions

such as height of retraction force on the power arm and its position on the

archwire in sliding mechanics. A 3D finite element method (FEM) was used to

simulate en masse anterior teeth retraction in sliding mechanics. The degree of

labiolingual tipping of the maxillary central incisor was calculated when the

retraction force was applied to different heights of a power arm set mesial or distal

to the canine. Placement of the power arm of an archwire between the lateral

incisor and canine enables orthodontists to maintain better control of the anterior

teeth in sliding mechanics. Both the biomechanical principles associated with the

tooth's center of resistance and the deformation of the archwire should be taken

into consideration for predicting and planning orthodontic tooth movement.

Anchor loss and sliding mechanics.

Heo W12 (2007) In their study to compare the amount of loss of anchorage, the

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between en masse retraction and two-step retraction of the anterior teeth.30 female

patients were chosen, who needed maximum posterior anchorage. The amount of

horizontal retraction of the maxillary anterior teeth was not different between the

two groups. Bodily and mesial movements of the upper molars occurred in both

groups. Approximately 4 mm of the retraction of the upper incisal edges resulted

from 1 mm of anchorage loss in the upper molars in both groups. They concluded

that there were no significant differences existed in the degree of anchor loss of

the upper posterior teeth and the amount of retraction of the upper

anterior teeth associated with en masse retraction and two-tep retraction .

M Barlow and K Kula13(2008) in their review article on Factors influencing

efficiency of sliding mechanics to close extraction space explain that clinical

research support laboratory results showed nickel-titanium coil springs produce a

more consistent force and a faster rate of closure when compared with active

ligatures as a method of force delivery to close extraction space along a

continuous arch wire; however, elastomeric chain produces similar rates of

closure when compared with nickel-titanium springs. Clinical and laboratory

research suggest little advantage of 200 g nickel-titanium springs over 150 g

springs.

Thiruvenkatachari B14 (2008)et al The purposes of their study were to measure

and compare the rates of canine retraction with titanium microimplant anchorage

and conventional molar anchorage. The sample comprised of 12 patients (8

female, 4 male; mean age, 19.7 years; range, 16-22 years) who were scheduled for

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microimplants 1.2 mm in diameter and 9 mm in length were placed between the

roots of the second premolar and the first molars. The implants were placed in the

maxillary and mandibular arches on the same side in 10 patients and in the maxilla

only in 2 patients. A brass wire guide and a periapical radiograph were used to

determine the implant position. After 15 days, the implants and the molars were

loaded with closed coil springs with a force of 100 g for canine retraction.

Preretraction and postretraction lateral cephalograms were taken and

superimposed for measuring the amount of retraction. The amount of canine

retraction was measured from pterygoid vertical in the maxilla and SN

perpendicular in the mandible. Mean canine retraction amounts were 4.29 mm in

the maxilla and 4.10 mm in the mandible on the implant-anchorage side, and 3.79

mm in the maxilla and 3.75 mm in the mandible on the molar-anchorage side. The

rates of canine retraction were 0.93 mm per month in the maxilla and 0.83 mm per

month in the mandible on the implant-anchored side, and 0.81 mm per month in

the maxilla and 0.76 mm per month in the mandible on the molar-anchored side.

Canine retraction proceeds at a faster rate when titanium microimplants are used

for anchorage.

Yukio Kojimaa and Hisao Fukuib15(2010) explained en-masse sliding

mechanics have been typically used for space closure. Tipping of the anterior

teeth occurred immediately after application of retraction forces. The force system

then changed so that the teeth moved almost bodily, and friction occurred at the

bracket-wire interface. Net force transferred to the anterior teeth was

approximately one fourth of the applied force. The amount of the mesial force

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Irrespective of the amount of friction, the ratio of movement distances between

the posterior and anterior teeth was almost the same. By increasing the applied

force or decreasing the frictional coefficient, the teeth moved rapidly, but the

tipping angle of the anterior teeth increased because of the elastic deflection of the

archwire. Finite element simulation clarified the tooth movement and the force

system in en-masse sliding mechanics. Long-term tooth movement could not be

predicted from the initial force system. The friction was not detrimental to the

anchorage. Increasing the applied force or decreasing the friction for rapid tooth

movement might result in tipping of the teeth.

Xu TM16(2010) et al conducted a pilot randomized clinical trial to investigate the

relative effectiveness of anchorage conservation of en-masse and 2-step retraction

techniques during maximum anchorage treatment in patients with Angle Class I

and Class II malocclusions. Sixty-four growing subjects (25 boys, 39 girls;

10.2-15.9 years old) who required maximum anchorage were randomized to 2

treatment techniques: en-masse retraction (n = 32) and 2-step retraction (n = 32);

the groups were stratified by sex and starting age. All patients used headgear, and

most had transpalatal appliances. Lateral cephalograms taken before treatment and

at the end of treatment were used to evaluate treatment-associated changes.

Differences in maxillary molar mesial displacement and maxillary incisor

retraction were measured with the before and after treatment tracings

superimposed on the anatomic best fit of the palatal structures. Differences in

mesial displacement of the maxillary first molar were compared between the 2

treatment techniques, between sexes, and between different starting-age groups.

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en-masse group than in the 2-step group (mean, -0.36 mm; 95% CI, -1.42 to 0.71

mm). The average mesial displacement of the maxillary first molar for both

treatment groups pooled (n = 63, because 1 patient was lost to follow-up) was 4.3

± 2.1 mm (mean ± standard deviation). This finding appears to contradict the

belief of many clinicians that 2-step canine retraction is more effective than

en-masse retraction in preventing clinically meaningful anchorage loss.

Nayef H. Felemban17(2013) explained that enmasse retraction of incisors has the

advantage of eliminating friction, which is created during sliding of canines and,

which usually contributes to loss of anchorage during space closure.Unlike,

enmasse retraction, a disadvantage of segmental retraction method is the creation

of unaesthetic spaces distal to lateral incisors, which persist for a considerably

long time during treatment.

FRICTION AND ANCHOR LOSS

Bednar JR18(1991) et al., conducted an in vitro study of simulated

canine retraction to evaluate the difference in frictional resistance between

stainless steel arch wires and steel and ceramic brackets with elastomeric, steel,

and self-ligation. Each bracket slot was 0.018 x 0.025 inch. The arch wires used

were 0.014-inch, 0.016-inch, 0.018-inch, 0.016 x 0.016-inch, and 0.016 x

0.22-inch stainless steel. The clinical significance of this study becomes apparent when

stainless steel brackets are used on the posterior teeth and ceramic brackets are

used on the anterior teeth. If sliding mechanics are used, the anterior teeth may be

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of the ceramic brackets. This could result in more posterior anchorage loss than

would be expected if only one type of bracket were used.

Husain N, Kumar A19( 2011) The purpose of this investigation was to determine

the kinetic frictional resistance offered by stainless steel and Titanium bracket

used in combination with rectangular stainless steel wire during in vitro

translatory displacement of brackets.In this study. Brackets: (All brackets used

had a torque of - 7° and an angulation of 0°): (1) Dynalock (Unitek) 0.018'' slot,

3.3 mm bracket width, (2) Mini Uni-Twin 0.018'' slot, 1.6 mm bracket width, (3)

Ultra-Minitrim 0.022'' slot 3.3 mm bracket width, (4) Titanium 0.022'' slot, 3.3

mm bracket width. Wires: (1) 0.016 x 0.022'' stainless steel (2) 0.017 x

0.025''stainless steel (3) 0.018 x 0.025'' stainless steel, elastomeric modules ,0.

009'' stainless steel ligature wires, hooks made of 0.021 x 0.025'' stainless steel

wires, super glue to bond the hooks to the base of the bracket, acetone to condition

the bracket and wires before testing and artificial saliva. Brackets were moved

along the wire by means of an Instron universal testing machine (1101) and forces

were measured by a load cell. All values were recorded in Newtons and then

converted into gms (1N-102 gm). 200 gm was then subtracted from these values

to find out the frictional force for each archwire/bracket combination. The results

showed that narrow brackets generated more friction than wider brackets.

Frictional force was directly proportional to wire dimension. Hence greater

applied force is needed to move a tooth with a bracket archwire combination

demonstrating high magnitudes of friction compared with one with a low

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Rajesh M20.(2014) studied to evaluate the amount and percentage

of anchor loss after initial leveling and aligning using a ROTH and MBT

prescription. Pre and post alignment lateral cephalograms & dental casts of 10

ROTH & 10 MBT patients. In the study, it was found that the amount

of anchor loss is greater in the ROTH group than the MBT group. This could be

due to the increased anterior tip in the ROTH prescription, compared to MBT. The

total anterior tip in ROTH is 270 and in MBT is 200. The additional tip of 70 in

ROTH prescription itself would have resulted in forward thrust of the anteriors.

The use of laceback and cinchbacks creates a statistically and clinically significant

increase in the anchorage loss specifically when the posterior anchorage is not

enhanced. In this study TPA was not used but studies have shown that passive

TPA has almost no effect on the clinician's need to preserve anchorage in the

correction of malocclusion. On the other hand, the TPA is an excellent way to

prevent molar rotation and maintain the original vertical and transverse dimension

when desired.

Frank CA, Nikolai RJ21 1980 Practitioners are aware of the presence of friction

in those orthodontic appliances where relative motion between bracket system and

arch wire occurs in ordinary deactivation processes.. The objective of this

investigation was to evaluate and compare frictional forces generated in an

experimental stimulation of the canine-retraction procedure on a continuous arch

wire. Six independent variables were chosen for study: arch wire size and shape,

bracket width and style, second-order angulation between bracket and passive

arch wire, arch wire material, ligature force and type of ligation, and interbracket

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bracket/arch wire angulation. With small and generally nonbinding angulations,

bracket width and ligature force were the dominant influences on level of friction.

As angulations were increased, producing binding between wire and bracket, this

variable itself became the controlling parameter. Wire shape and arch wire

stiffness in bending, a function of three of the variables studied, apparently

exerted substantial influence on frictional-force magnitude at relatively high

angulations.

Tidy22( 1989) explained that with brackets out of alignment, arch wire stiffness

strongly influences forces normal to the points of contact and hence friction. In a

well-aligned arch, forces that result from arch wire deflection are not important

and friction is largely independent of arch wire stiffness. However, kinks or

deposits along a closely fitting arch wire are more likely to lead to binding in the

slot and clearance is therefore of some secondary importance. The component of

friction caused by active torque may also be greater for a closely fitting wire

because of its greater torsional stiffness and the reduced play between wire and

slot. To reduce friction clinically, some practitioners prefer the use of round wire,

or they reduce rectangular wire in the buccal segments to a more rounded cross

section. Round wires, of course, eliminate friction caused by active torque. Round

wires generally produce less friction than rectangular wire when engaged in

brackets out of alignment because of their greater flexibility.

Dieter Drescheret al.23(1989) explained that guiding a tooth along an arch wire

will results in a counteracting frictional force. Clinically, a mesiodistally applied

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friction-15

testing assembly simulating three-dimensional tooth rotations was constructed to

study factors affecting friction magnitude. Five wire alloys (standard stainless

steel, Hi-T stainless steel, Elgiloy blue, nitinol, and TMA) in five wire sizes

(0.016, 0.016 × 0.022, 0.017 × 0.025, 0.018, and 0.018 × 0.025 inch) were

examined with respect to three bracket widths (2.2, 3.3, and 4.2 mm) at four levels

of retarding force (0, 1, 2, and 3 N). The following factors affected friction in

decreasing order: retarding force (biologic resistance), surface roughness of wire,

wire size (vertical dimension), bracket width, and elastic properties of wire. The

effective force has to increase twofold to overcome the friction resulting in a

hazardous overload of the anchorage units.

Sunil Kapila24, et al.,(1990) investigated the effects of wire size and alloy on

frictional force generated between bracket and wire during in vitro translatory

displacement of bracket relative to wire. Stainless steel (SS), cobalt-chromium

(Co-Cr), nickel-titanium (NiTi), and β-titanium (β-Ti) wires of several sizes were

tested in narrow single (0.050-inch), medium twin (0.130-inch) and wide twin

(0.180-inch) stainless steel brackets in both 0.018- and 0.022-inch slots. The wires

were ligated into the brackets with elastomeric ligatures. Bracket movement along

the wire was implemented by means of a mechanical testing instrument, and

frictional forces were measured by a compression cell and recorded on an X-Y

recorder. β-Ti and NiTi wires generated greater amounts of frictional forces than

SS or Co-Cr wires did for most wire sizes. Increase in wire size generally resulted

in increased bracket-wire friction. The wire size-alloy interaction on the

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Tselepis M25, Brockhurst P, West VC. (1994) in their study quantifies the

dynamic frictional force of sliding between different modern orthodontic brackets

and arch wires. From the multitude of factors involved in the frictional process,

the following were selected for investigation: arch wire material, bracket material,

bracket-to-arch wire angulation, and lubrication (artificial saliva). The frictional

force involved in sliding a ligated arch wire through a bracket slot was measured

with a universal materials testing machine. A four-way analysis of variance was

used to assess the results. Of the four factors investigated, all were found to have a

significant influence on friction. Friction increased with bracket-to-arch wire

angulation. Lubrication significantly reduced friction.The forces observed suggest

that friction may be a significant influence on the amount of applied force

required to move a tooth in the mouth. Hence, arch wire and bracket selection may

be an important consideration when posterior anchorage is critical.

D.J. Michelberger26, (2000) explained that Frictional resistance at the

bracket-archwire interface has been demonstrated to impede tooth movement when sliding

mechanics are used. They studied the coefficients of friction of titanium and

stainless steel brackets in conjunction with stainless and ion-implanted

beta-titanium archwires using a single contact interface between the brackets and

archwires. .They concluded that round stainless steel wires demonstrated lower

coefficients of kinetic friction than the flat stainless steel wire surfaces.

A Buzzoni R, Elias CN27, (2011) explaind that low friction system is based on the

free flow between the wire and the bracket slot. To assure this free flow between

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flow the clinician will choose an initial wire of round shape with a very small

diameter. This difference in size between the wire and the lumen of the bracket

leaves an empty space that will minimize binding. A small round shape wire will

also minimize binding at the entrance and exit of the bracket. The partial

engagement minimizes tipping of the teeth. The combination of small round wires

and no binding exerts lower forces on the periodontal membrane of the teeth in the

system. They introduced the “Biozone concept.” The Biozone is the area in the

periodontal membrane where the vascular tissues bathe in collagen fibers, ideally

in balance with the intra and extra vascular forces. The higher friction observed in

rectangular wires can be explained by the greater contact, or greater likelihood of

contact with the bracket slots, which affects the surface component that makes up

friction forces. We will rarely observe friction values in rectangular wires that are

lower than the round counterparts.

Dholakia28 KD 2012 explain that friction is inevitable. To overcome this

frictional resistance, excess force is required to retract the tooth along the archwire

ie, individual retraction of canines, en masse retraction of anterior teeth, in

addition to the amount of force required for tooth movement. The anterior tooth

retraction force, in addition to excess force (to overcome friction), produces

reciprocal protraction force on molars, thereby leading to increased anchorage

loading. This article reinforce the fact that clinically, friction increases anchorage

loading in all three planes of space, considering the fact that tooth movement is a

quasistatic process rather than a purely continuous or static one, and that

conventional ways of determining the effects of static or dynamic friction on

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anatomical resistance units and a complex muscular force system). better choice

for long-term stability.

MICROIMPLANTS

Creekmore TD, Eklund MK2(1983) The first clinical report in the literature of

the use of TADs appeared in 1983 when Creekmore and Eklund used a vitallium

bone screw to treat a patient with a deep impinging overbite. The screw was

inserted in the anterior nasal spine to intrude and root and correct the upper

incisors using an elastic from the screw to the incisors 10 days after the screw was

placed.

Costa A29, Raffainl M, Melsen B(1998) In this study,the problems related to

anchorage for orthodontic tooth movements in patients with deficient dentition are

discussed, and various solutions suggested in the literature, including "onplants,"

implants, and zygoma wires, are evaluated. A miniscrew is presented as

alternative anchorage. Miniscrews are easily placed and removed and can be

loaded immediately following insertion. However, stability is limited after loading

with torsion.

In 2000, Park HS30, in his study, a skeletal Class II patient was treated with

sliding mechanics using M.I.A.(micro-implant anchorage)explained that the

maxillary micro-implants provide anchorage for retraction of the upper anterior

teeth.. The micro-implants remained firm and stable throughout treatment. This

new approach to the treatment of skeletal class II malocclusion has the following

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the simultaneous retraction of the six anterior teeth. Early change of facial profile

motivating greater cooperation from patients These results indicate that the M.I.A.

can be used as anchorage for orthodontic treatment. The use of M.I.A. with sliding

mechanics in the treatment of skeletal Class II malocclusion increases the

treatment simplicity and efficiency. ..

Hyo-Sang Park, Tae-Geon Kwon31, (2004) concluded that Sliding mechanics

with maxillary microscrew implants provide anchorage for bodily retraction with

a slight intrusion by making the force pass near the center of resistance. The

maxillary posterior teeth and anterior teeth can both be retracted without

anchorage loss. When microscrew implants are used, clinicians can retract six

anterior teeth altogether without anchorage loss even with the use of preadjusted

appliances.

According to Eric J. W. Liou,32 ,a Betty C. J. Pai, and James C. Y. Lin, (2004),

Miniscrews provides stable anchorage for orthodontic tooth movement but do not

remain absolutely stationary like an endosseous implant throughout orthodontic

loading. They might move according to the orthodontic loading in some patients.

To prevent hitting any vital organs because of miniscrew displacement, it is

recommended that miniscrews be placed in a non–tooth bearing area that has no

foramen, major nerves, or blood vessel pathways, or in a tooth-bearing area

allowing a 2-mm safety clearance between the miniscrew and dental root.

Aldo Carano33, Stefano Velo, (2005) demonstrated the versatility and technical

advantages of skeletal anchorage.They explained the advantages of miniscrews

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number or positions of the teeth, shorter treatment time, with no need to prepare

dental anchorage, independence of patient cooperation, patient comfort, low cost.

Badri Thiruvenkatachari,34 A. Pavithranand,b K. Rajasigamani,c and Hee

Moon Kyungd (2006) The purpose of this study was to compare and measure the

amount of anchorage loss with titanium microimplants and conventional molar

anchorage during canine retraction. Subjects for this study comprised 10

orthodontic patients (7 women, 3 men) with a mean age of 19.6 years (range, 18 to

25 years), who had therapeutic extraction of all first premolars. After leveling and

aligning, titanium microimplants 1.3 mm in diameter and 9 mm in length were

placed between the roots of the second premolars and the first molars. After 15

days, the implants and the molars were loaded with closed-coil springs for canine

retraction. Lateral cephalograms were taken before and after retraction, and the

tracings were superimposed to assess anchorage loss. The amount of molar

anchorage loss was measured from pterygoid vertical in the maxilla and

sella-nasion perpendicular in the mandible.Mean anchorage losses were 1.60 mm in the

maxilla and 1.70 mm in the mandible on the molar anchorage side; no anchorage

loss occurred on the implant side. They concluded that Titanium microimplants

can function as simple and efficient anchors for canine retraction when maximum

anchorage is desired.

Hyo-Sang Park35,a Seong-Hwa Jeong,b and Oh-Won Kwonc(2006) in their

study on miniscrews found that miniscrews used as orthodontic anchorage should

be loaded early to reduce treatment time and should be removed after treatment. In

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between the roots of the teeth, or in the palatal or retromolar area, in dental

implants, mobility due to lack of osseointegration is a sign of failure. For screw

implants used as orthodontic anchorage, however, mobility might not represent

failure. They checked the mobility of the screw implants 5 to 8 months after

placement, during loading. Deguchi et al postulated that less osseointegration does

not necessarily indicate a negative finding.. Therefore, minimal mobility can be

allowed in orthodontic screw implants.

Neal D. Kravitza36 and Budi Kusnotob(2007) described the risk factors with

miniscrew placement. They said that nerve injury can occur during placement of

miniscrews in the maxillary palatal slope, the mandibular buccal dentoalveolus,

and the retromolar region. Peri-implant soft-tissue type, health, and thickness can

affect stationary anchorage of the miniscrew. To account for potential migration,

the clinician should allow a 2-mm safety clearance between theminiscrew and any

anatomical structures.

Madhur Upadhyay37, Sumit Yadav, and Sameer Patil (2008) did a

caphalometric study to determine the efficiency of mini-implants as intraoral

anchorage units for en-masse retraction of the 6 maxillary anterior teeth when the

first premolars are extracted compared with conventional methods of anchorage

reinforcement.The mini-implants placed in the interdental bone between the

maxillary first molar and second premolar proved to be efficient for intraoral

anchorage reinforcements for en-masse retraction and intrusion of the maxillary

anterior teeth. They concluded that there was no anchorage loss with

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conventional methods of anchorage reinforcements. However, a decrease in

intermolar width was noted. No significant differences were found in the rates of

retraction between the 2 groups. A finite element analysis was done by Sang-jin

sung,Gang-won jang to examine the effective en-masse retraction design with

orthodontic mini- implant anchorage .Their results revealed that the height of the

anterior retracton hook and the placement of the compensating curves had limited

effects on the labial crown torque of the central incisors for enmasse retraction.For

high mini-implant traction and 8 mm anterior retraction condition,the retraction

force vector was applied above the center of resistance for the 6 anterior teeth,but

no bodily retraction of the 6 anterior teeth occurred.

Shingo Kuroda38, Kazuyo Yamada, Toru Deguchi, Hee-Moon Kyung, and

Teruko Takano-Yamamotoe (2009) compared treatment outcomes of patients

with severe skeletal Class II malocclusion treated using miniscrew anchorage or

traditional orthodontic mechanics of headgear and transpalatal arch. Pretreatment

and posttreatment lateral cephalograms were analyzed. The results showed , Both

treatment methods, achieved acceptable results as indicated by the reduction of

overjet and the improvement of facial profile. However, incisor retraction with

miniscrew anchorage did not require patient cooperation to reinforce the

anchorage and provided more significant improvement of the facial profile than

traditional anchorage mechanics (headgear combined with transpalatal arch).They

Concluded, Orthodontic treatment with miniscrew anchorage is simpler and more

useful than that with traditional anchorage mechanics for patients with Class II

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Basha AG39, Shantaraj R, Mogegowda SB( 2010) their study was conducted to

measure and compare the difference between rate of en-masse retraction with

molar anchorage and mini-implant.A comparative study consisting of 14 patients

(all females) randomized into 2 groups. Seven in group I (nonimplant) molar was

used as anchor for en-masse retraction of anterior teeth (mean age 16 years SD +/-

1.41). In group II (implant), mini-implant was used as anchorage to retract the

anterior teeth (mean age 17.36 SD +/- 1.35). In both groups, all first premolars

were extracted. After leveling and aligning, surgical steel mini-implant of 1.3 mm

in diameter and 8 mm in length were placed between the roots of second premolar

and first molar in the maxilla in the implant group. Implants were immediately

loaded with 2 N of force. In nonimplant group molar was used as anchorage. The

retraction and postretraction lateral cephalograms were taken. Rate of retraction

and anchor loss were measured by using pterygoid vertical in maxilla. Student t

test were used to analyze the treatment charges in 2 groups. Mean anchor loss in

maxilla in nonimplant group. No differences in the mean rate of retraction time

were noted in both groups.

Papadopoulos MA40, Papageorgiou SN, Zogakis IP. 2011 Preliminary

three-dimensional analysis of tooth movement and arch dimension change of the

maxillary dentition in Class II division 1 malocclusion treated with first premolar

extraction: conventional anchorage vs. mini-implant anchorage.

Jambi S41, et al, (2014) The objective of their 3-arm parallel randomized clinical

trial was to compare the effectiveness of temporary anchorage devices (TADs),

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treatment of patients with malocclusions that required maximum anchorage. The

study included 78 patients (ages, 12-18 years; mean age, 14.2 years) who needed

maximum anchorage. The primary outcome was mesial molar movement during

the period in which anchorage supplementation was required. The secondary

outcomes were duration of anchorage reinforcement, number of treatment visits,

number of casual and failed appointments, total treatment time, dento-occlusal

change, and patients' perceptions of the method of anchorage supplementation.

The randomization was based on a computer-generated pseudo-random code with

random permuted blocks of randomly varying size. There was no difference in the

effectiveness between the 3 groups in terms of anchorage support. There were

more problems with the headgear and Nance buttons than with the TADs. The

quality of treatment was better with TADs. As a result, TADS might be the

preferred method for reinforcing orthodontic anchorage in patients who need

maximum anchorage.

BIMETRIC SYSTEM

John C42. Bennett, Richard P. Mclaughlin, (1990) concluded in their study that

archwire thinning is effective, but have discarded it because of reduced tooth

control in the thinned areas. Selective torque application is more effective,

especially in the incisor regions. Flat wires can be adjusted quickly and easily at

chairside to carry a customized 10-15º of incisor torque. Likewise, molar torque

can be selectively applied to resist mesial movement of the molars and create a

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Schudy43, F.F. and Schudy, G.F(1975) introduced biometric system.

Giancotti4, A. and Gianelly, (2001) A.A.: in their study explained

three-dimensional control in extraction cases using a Bithree-dimensional approach, the

double section archwire resulted to be an effective alternative option to optimize

the lateral and posterior sliding mechanics with controlled tipping and by the

application of lighter forces.

Cannon JL44 (1985) explained about the advantages of Dual flex wires which are

given as Dual Flex-l, Dual Flex-2, and Dual Flex-3. Dual Flex-1 consists of a

front section made of 0.016-inch round Titanal (Lancer Orthodontics) and a

posterior section made of 0.016-inch round steel. The flexible front part easily

aligns the anterior teeth and the rigid posterior part maintains the anchorage and

molar control by means of the “V” bend, mesial to the molars. It is used at the

beginning of treatment. The Dual Flex-2 consists of a flexible front segment

composed of an 0.016 × 0.022-inch rectangular Titanal and a rigid posterior

segment of round 0.018-inch steel. The Dual Flex-3, however, consists of a

flexible front part of an 0.017 × 0.025-inch Titanal rectangular wire and a

posterior part of 0.018 square steel wire. The Dual Flex-2 and 3 wires establish

anterior anchorage and control molar rotation during the closure of posterior

spaces. They also initiate the anterior torque.

José L. Zuriarrain45(1996) experimented many bidimensional systems including

The Spectrum bracket, combination bracket, based on a Siamese-type bracket

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used simultaneously on the same dental arc. They are formed by a flexible

nickel-titanium tandem arch wire located in the horizontal slot and a vertical stabilizing

arch wire inserted in the gingival wing slot. The flexible Titanal tandem wire can

be made of round 0.016, square 0.018 × 0.018, or rectangular 0.016 × 0.022-inch.

The second arch wire is a round 0.018-inch Australian steel arch wire, with

intrusive bends at the molar and distal to the canine. These multiple arch wires are

used to progressively align and torque the crowns and roots (achieved with the

flexible Titanal arch wire in the straight wire slots), while, simultaneously, the

arch form and vertical position of the molars and incisors are maintained by a

rigid steel arch wire in the gingival slots, He concludes that. Combining treatment

mechanics has proven very useful in the treatment of all types of malocclusions.

Its versatility allows the use of either technique (edgewise or light wire) or both

techniques; thereby, obtaining the advantage of being able to use the most

effective attributes of either technique while eliminating disadvantages or the less

effective mechanics of either technique.

Greco M46, Giancotti A(2007). The Bidimensional technique is an edgewise

technique in which 2 different sized vertically slotted brackets are used. On the

central and lateral incisors, .018" x .022" brackets are placed on the central and

lateral incisors and .022" x .028" brackets are placed on the canines, molars and

premolars. The maxillary incisor brackets are programmed. All movements,

including bodily retraction of the maxillary incisors are produced by sliding

mechanincs. When retracting maxillary incisors, an .018" x. 022" wire which fills

the vertical portion of the brackets, providing torque control, is inserted and 300

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.018" x .022" wire is undersized relative to the canine, premolar and molar

brackets and can readily slide through the brackets and tubes.

Giancotti A47, Greco M.(2010) They illustrated a modified archwire during

space closure with anterior anchorage in Bidimensional Tecnique. The archwire

used was a .018x.025 SS on the anterior teeth and .018 SS on the lateral and

posterior teeth in order to maintain anterior anchorage using torque and uprighting

springs as showed in Bidmensional Technique but exerting lighter forces (150 g).

The double section archwire resulted to be an effective alternative option to

optimize the lateral and posterior sliding mechanics with controlled tipping and by

the application of lighter forces.

Tomio Ikegami5, describes the Hybrid Orthodontic Treatment System (HOTS),

an innovative method used in first premolar extraction cases.It comprises the

following three components: (1) a miniscrew, (2)dual-dimension wires, and (3)

multiloop edgewise archwires consists of four clearly defined treatment steps: (1)

setup, (2) leveling,(3) separate but simultaneous anterior and canine teeth

retraction, and (4) final adjustment. HOTS achieves a predictable treatment

outcome with a shorter treatment time.

Daniele Cantarella48, Luca Lombardo, and Giuseppe Siciliani (2013) This

article presented a clinical methodology aimed at minimizing binding in fixed

orthodontic appliances. The dynforce archwire has a full size anterior segment

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(e.g. .018×.025 or .018×.022), and is used in the orthodontic phase of space

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MATERIALS AND METHODS

Among the patients reported to the Department of Orthodontics and

Dentofacial Orthopaedics, Tamilnadu Government Dental College and Hospital,

Chennai, for orthodontic treatment ,sixteen patients who fulfilled the inclusion and

exclusion criteria were chosen as subjects in this study.Ethical clearance for

conducting the study was obtained from the Institutional ethical committee of

Tamilnadu Government Dental College and Hospital, Chennai .The study subjects

were randomly selected for experimental group and control group.

Inclusion criteria:

 Age group - 18-25

 Patients undergoing orthodontic treatment with all the four 1st premolars extracted, and planned for enmasse retraction with Pre-adjusted Edgewise

technique (MBT prescription).

 Patients whose treatment plan includes skeletal anchorage with miniscrews after completion of leveling and alignment

Exclusion criteria

 Patients with Skeletal malocclusion

 Medically compromised patients

 Patients under prolonged medication.

 history of trauma

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All the patients (16) were randomly allocated into group A and Group B,

with 8 patients in each group.No gender bias was made.

 Group A: 8 patients undergoing orthodontic treatment, to continue with Dual dimensional wires.

 Group B: 8 patients undergoing orthodontic treatment with conventional rectangular wire.

Armamentarium used for group A:

 Dual dimensional wire- 021 x .021x.018 (Speed System)

 Microimplant-1.5x 8 mm titanium implants from (Dentos)

 Driver for microimplant (Dentos)

 NiTi closed coil spring-9 mm(ormco)

 Plier (weingart)

 S hook(ormco)

 Modules(ormco)

 Study models (orthokal/stone)

 Lateral cephalograms (Planmeca PM 202 CC Proline)

 Vernier calipers(Robust)

 Dontrix gauge (Robust)

 Mouth mirror and probe

Armamentarium used for group B:

 Rectangular stainless steel wires- 021 x .025(G &H)

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 Driver for microimplant (Dentos)

 NiTi closed coil spring-9 mm(ormco)

 Plier (weingart)

 S hook(ormco)

 Modules (ormco)

 Study models (orthokal/stone)

 Lateral cephalogram (Planmeca PM 202 CC Proline)

 Vernier calipers(Robust)

 Dontrix gauge(Robust)

 Mouth mirror and Probe

Clinical procedure

After the leveling and alignment stage,the patients were grouped into

two,one group to be treated with dual dimensional wire and the other to be treated

with conventional rectangular stainless steel(21x25) wire.Impressions were taken

with alginate and models were poured with Orthokal. Measurements were made

for the position of canine, premolars and molars. (To).Preoperative lateral

cephalogram was taken with ‘L’ shaped wire placed in the molar buccal tube on

both the sides for easy identification52 using cephalometric and panaromic

radiographic unit – PLANMECA PM 202 CC PROLINE), by a single technician

with same magnification.

A 0.017x 0.025-inch stainless steel wire is shaped in the form of an “L”

with 0.5 cm of vertical length and 1 cm of horizontal length. The horizontal